Does all work and no play make Jack a dumb boy as well as a dull one? This column presents one of the first empirical studies on the effects of sporting activity on the cognitive ability of children in Germany.

Physical inactivity is a growing problem. It contributes to the obesity epidemic and is particularly worrisome among the youngest in society. As a result, many countries have programmes aimed at increasing the physical activity of children – the "Let's Move!" campaign led by the US first lady, Michelle Obama, is a prominent example.

Folklore around the world tells us that physical activities are good for a child's development. Moreover, many scientific studies have shown a positive association between the level of physical activity and measures of children's health, skills, and wellbeing (Strong et al 2005). Yet, empirical evidence, at least about the causal effect of physical activities on the non-health outcomes, is scarce.

Our study (Felfe et al 2011) aims to fill this gap and to shed some light on the effect of sport activities on smaller children's human-capital formation. Our results reveal that active sport club participation leads to improvements in children's cognitive and non-cognitive skills, which are of similar size to the ones found for largescale educational programmes.

So far, the economic literature has mainly focused on sport activities among adolescents. A positive relationship between participation in high school sport and educational attainment, on the one hand, and professional success, on the other, is well established (Barron et al 2000, Eide and Ronan 2001, Pfeiffer and Cornelissen 2010, Stevenson 2010). Yet, the underlying mechanism is not yet well understood. In particular, the question of when and through which mechanism sport exerts its influence on people's educational and professional success remains open.

When addressing this question it is crucial to bear in mind that cognitive and non-cognitive abilities already acquired early in life are key determinants of success later in life (Heckman 2006). Thus, the focus of our study lies on sport participation during childhood. To be more precise, we focus on participation in sport clubs among children aged three to ten years in Germany. In Germany sport clubs are the key institutions organising sport activities of children. According to the German Olympic Association (DOSB, Deutscher Olympischer Sportbund 2009), 76% of boys and 59% of girls aged seven to fourteen are playing sports in a club. This is in stark contrast with the US, for example, where youth sport is much more organised by schools. In Germany most child and youth sport , both for leisure and competition, is organised in clubs. Schools play only a minor role.

Measuring the effect of sport during childhood

Our empirical analysis draws upon a cross-sectional (medical) survey for Germany, the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). This dataset provides us not only with a wide array of children's cognitive and non-cognitive skill measures, but also with detailed information on children's health, sport participation, and their family background (5,632 children). Our main empirical approach is based on a matching estimation strategy. The basic idea is that we compare the outcomes of children who participate in sport with children who do not participate but are almost identical in other aspects, such as sex and age, their parents’ education and income, their brothers and sisters, their parents’ parenting style, or the characteristics of the neighbourhood they live in. As the KiGGS dataset contains a very rich set of characteristics, especially regarding parenting style of parents, we can match children on all-important observable characteristics.

Results

Our findings indicate strong positive effects of participation in sport on children's cognitive and non-cognitive skills (see Table 1). We normalise our measures of children's skills to be zero on average and have a standard deviation of one. In so doing we can interpret the size of the effects in relationship to the general variation in children's skills (measured by one standard deviation (henceforth, sd). Both cognitive skills, measured by overall school grades, and overall non-cognitive skills improve by 0.13 sd. The latter effect is mainly driven by a reduction in emotional problems (0.10 sd) and in peer problems (0.22 sd). The fact that children who engage in sport also fare better in terms of health (0.12 sd) and general wellbeing (0.11 sd) support these findings.

The size of the effects is in a similar range to the effects other studies find for largescale educational programmes. Head Start for instance, one of the most studied educational programmes in the US, has been shown to lead to improvements in children’s non-cognitive skills of around 0.2 sd and in children’s cognitive skills of around 0.06 sd (Currie and Almond 2011).

Empirical challenges: Is the effect driven by better parents or better children?

It is easy to cast into doubt whether our findings are driven by the fact that children, who are more likely to engage in sport, are endowed with a priori better skills or stem from a more advantaged family background. To the extent that these differences are unobserved, our suggested empirical approach may fail to estimate the causal effect of sport participation on children's development. In order to address these issues we pursue the following two alternative strategies.

First, we take advantage of the panel dimension of a further dataset, the German Child Panel. The longitudinal nature of this dataset allows us to match children on their initial level of sport activity, skill endowment, and health conditions.

Second, we exploit differences in the local availability of sport facilities. A better local supply of sport facilities should lead to higher sport participation among children, but should not be directly linked to an improvement in children's development (except via increased sport participation). Thus, it acts as an exogenous shifter of children's sport participation.

Discussion

Our results highlight the importance of physical activities for children's development. Encouraging children to participate in sport and providing the necessary infrastructure should therefore be, and in many countries already is, an important policy objective, although this statement has to be qualified by a cost-benefit analysis. Moreover, our results provide evidence that the positive effects of playing sports in a club are partially explained by an increase in physical activity as sport club participation does not crowd out other sport activities. The effects are strongest in cities, where children have fewer opportunities to be physically active outside of sport clubs. One further explanation for our findings is a reduction in passive activities such as watching TV. Nevertheless, ‘playing sports in a club’ has still many more dimensions, which, given the data at hand, we are not able to explore. Participating in a sport club exposes children to cooperation with other children in a team, which may also make them better team players in other situations in life. Playing sports in a club comes often along with participation in competitions. Victory in competition may raise children's self-esteem while defeat, despite eventual negative effects on children’s self-esteem, may teach them how to deal with such a situation. Future research should therefore try to dig deeper into the mechanisms through which sport activities may influence skill formation and disentangle the various channels through which the effect may work.

Table 1. Matching estimates for the impact of sport on children's development